From foodconsumer.org
The benefits of green tea in reducing an important risk factor for heart disease
By news release
Jul 2, 2008 - 9:16:34 PM
Contact: Céline Colas
ccolas@escardio.org
33-492-947-609
European Society of Cardiology
More evidence for the beneficial
effect of green tea on risk factors for heart disease has emerged in a
new study reported in the latest issue of
European Journal of Cardiovascular Prevention and Rehabilitation.1
The study found that the consumption of green tea rapidly improves the
function of (endothelial) cells lining the circulatory system;
endothelial dysfunction is a key event in the progression of
atherosclerosis.
The study, performed by Dr Nikolaos
Alexopoulos and colleagues at the 1st Cardiology Department, Athens
Medical School in Greece, was a randomised trial involving the diameter
measurement (dilatation) of the brachial artery of healthy volunteers
on three separate occasions - after taking green tea, caffeine, and hot
water (for a placebo effect). The measurements were taken at 30, 90 and
120 minutes after consumption. Dilatation of the brachial artery as a
result of increased blood flow (following a brief period of ischaemia
of the upper limb) is related to endothelial function and is known to
be an independent predictor of cardiovascular risk.2
Results
showed that endothelium-dependent brachial artery dilatation increased
significantly after drinking green tea, with a peak increase of 3.9 per
cent 30 minutes after consumption. The effect of caffeine consumption
(or hot water) was not significant.
While black tea has been
associated with improved short and long-term endothelial performance,
this is the first time that green tea has been shown to have a
short-term beneficial effect on the large arteries. Another study has
already shown that green tea reverses endothelial dysfunction in
smokers.
Green tea, which originates in China but is now
consumed throughout the world, is made with pure leaves, and has
undergone little oxidisation during processing. The cardiovascular
benefits of all teas - as well as dark chocolate and red wine - are
attributed to the flavonoids they contain and their antioxidant
activity.3 However, says investigator Dr Charalambos Vlachopoulos,
flavonoids in green tea are probably more potent antioxidants than in
black tea because there has been no oxidisation.
"These
findings have important clinical implications," says Dr Vlachopoulos.
"Tea consumption has been associated with reduced cardiovascular
morbidity and mortality in several studies. Green tea is consumed less
in the Western world than black tea, but it could be more beneficial
because of the way it seems to improve endothelial function. In this
same context, recent studies have also shown potent anticarcinogenic
effects of green tea, attributed to its antioxidant properties."
###
Notes
1. Alexopoulos N, Vlachopoulos C, Aznaouridis K, et al. The
acute effect of green tea consumption on endothelial function in
healthy individuals. European Journal of Cardiovascular Prevention and
Rehabilitation 2008; 15: 300-305.
* The EJCPR is the official journal of the European Association
for Cardiovascular Prevention and Rehabilitation of the European
Society of Cardiology.
2. The study measured flow-mediated
dilatation of the brachial artery, which is predominantly dependent on
the release of nitric oxide from the endothelium and represents a well
accepted estimate of endothelial function.
Measurement of the brachial arteries was performed by high-resolution ultrasound.
3.
Flavonoids are naturally found in many plants and have been shown to
have many different biological effects in humans. Their antioxidant
effects have been found in red wine, red grapes and dark chocolate.
Oxidative stress, which has been associated with many human diseases,
can be reversed by antioxidant intake.
* More information on this press release and a PDF of the paper are available from the ESC's press office at
press@escardio.org
* The corresponding author of the study is Dr Charalambos Vlachopoulos, Athens Medical School, Athens
Tel: + 30 6972 272727
cvlachop@otenet.gr